In 1889, a year after both he and Heinrich Hertz discovered electromagnetic waves and for the first time demonstrated the truth of Maxwell's great theory of the electromagnetic field, physicist Oliver Lodge (1851-1940) published his deepest reflections on the nature and meaning of electricity, how it originates, and its different manifestations. There had been great scientific advances - the work of Faraday and Maxwell, his own experiments and those of Hertz - and a revolution in technology. There were also puzzling questions. What is the connection between electricity and the ether that occupies space? How does electricity manifest itself in matter? Why does it come in fixed units? The discovery of the electron eight years later would offer crucial answers. Always lucid and direct, with a gift for making the difficult seem simple, Lodge engages the reader with his fascination for the subject, much as he did in his famous lectures.